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Результаты 201-210 из 2,512
Does an analysis of polychlorinated biphenyl (PCB) distribution in mountain soils across China reveal a latitudinal fractionation paradox? Полный текст
2014
Zheng, Qian | Nizzetto, Luca | Mulder, Marie D. | Sáňka, Ondřej | Lammel, Gerhard | Li, Jun | Bing, Haijian | Liu, Xin | Jiang, Yishan | Luo, Chunlin | Zhang, Gan
Organic and mineral soil horizons from forests in 30 mountains across China were analysed for polychlorinated biphenyl (PCB). Soil total organic carbon (TOC) content was a key determinant of PCB distribution explaining over 90% of the differences between organic and mineral soils, and between 30% and 60% of the variance along altitudinal and regional transects. The residual variance (after normalization by TOC) was small. Tri- to tetra-CB levels were higher in the South in relation to high source density and precipitation. Heavier congeners were instead more abundant at mid/high-latitudes where the advection pattern was mainly from long range transport. This resulted in a latitudinal fractionation opposite to theoretical expectations. The study showed that exposure to sources with different characteristics, and possibly accumulation/degradation trends of different congeners in soils being out-of-phase at different latitudes, can lead to an unsteady large scale distribution scenario conflicting with the thermodynamic equilibrium perception.
Показать больше [+] Меньше [-]Lead and other elements in house dust of Japanese residences – Source of lead and health risks due to metal exposure Полный текст
2014
Yoshinaga, Jun | Yamasaki, Kumiko | Yonemura, Ayumi | Ishibashi, Yuri | Kaido, Takaya | Mizuno, Kodai | Takagi, Mai | Tanaka, Atsushi
The levels of 25 elements in house dust collected from 100 general Japanese residences were measured. Factor analysis was applied on the multi-element data to explore source of Pb (median concentration 49.1 mg/kg) in house dust. Six factors were extracted and Pb was found to have great loading on the fifth factor with Sb and Sn, suggesting solder (Sn), and plastic and metals (Sb) may be the sources of Pb in the house dust of Japanese residences. No significant loading was found on soil-related factors indicating non-significant contribution of Pb in track-in soil. Seven heavy metals (Cd, Cu, Mo, Pb, Sb, Sn, and Zn) were found in house dust at >10 times more condensed than crustal abundance. Health risk of these elements to children via the ingestion of house dust was estimated based on the comparison with tolerable daily intake and found to be non-significant for most of the elements.
Показать больше [+] Меньше [-]Long-term inverse modeling of Chinese CO emission from satellite observations Полный текст
2014
Yumimoto, Keiya | Uno, Itsushi | Itahashi, Syuichi
Carbon monoxide (CO) emissions in China in 2005–2010 were estimated by inversion, using the Green's function method from vertical CO profiles derived from MOPITT Version 5 satellite data and a tagged CO simulation, and validated with independent in situ observations from the World Data Centre for Greenhouse Gases. Modeling with a posteriori emission successfully reproduced CO outflow from the continent to the East China Sea, Sea of Japan, and Japanese islands during winter and spring, and compensated for underestimates in central and eastern China in summer. A posteriori emissions showed large seasonal variations in which December and March emissions were on average 23% larger than August emissions, consistent with other studies. Estimated Chinese CO emissions were 184.4, 173.1, 184.6, 158.4, 157.4, and 157.3 Tg/year for 2005–2010, respectively. The decrease after 2007 is partly attributed to Chinese socioeconomic conditions and improved combustion efficiency.
Показать больше [+] Меньше [-]Is there a relationship between earthworm energy reserves and metal availability after exposure to field-contaminated soils? Полный текст
2014
Beaumelle, Léa | Lamy, Isabelle | Cheviron, Nathalie | Hedde, Mickaël
Is there a relationship between earthworm energy reserves and metal availability after exposure to field-contaminated soils? Полный текст
2014
Beaumelle, Léa | Lamy, Isabelle | Cheviron, Nathalie | Hedde, Mickaël
Generic biomarkers are needed to assess environmental risks in metal polluted soils. We assessed the strength of the relationship between earthworm energy reserves and metal availability under conditions of cocktail of metals at low doses and large range of soil parameters. Aporrectodea caliginosa was exposed in laboratory to a panel of soils differing in Cd, Pb and Zn total and available (CaCl2 and EDTA-extractable) concentrations, and in soil texture, pH, CEC and organic-C. Glycogen, protein and lipid contents were recorded in exposed worms. Glycogen contents were not linked to the explaining variables considered. Variable selection identified CaCl2 extractable metals concentrations and soil texture as the main factors affecting protein and lipid contents. The results showed opposite effects of Pb and Zn, high inter-individual variability of biomarkers and weak relationships with easily extractable metals. Our results support the lack of genericity of energy reserves in earthworms exposed to field-contaminated soils.
Показать больше [+] Меньше [-]Is there a relationship between earthworm energy reserves and metal availability after exposure to eld contaminated soils? Полный текст
2014
Beaumelle, Léa | Lamy, Isabelle | Cheviron, Nathalie | Hedde, Mickael | Physicochimie et Ecotoxicologie des SolS d'Agrosystèmes Contaminés (PESSAC) ; Institut National de la Recherche Agronomique (INRA) | ADEME; INRA-EA [3829]
Avec les remerciements pour Jodie Thénard | Generic biomarkers are needed to assess environmental risks in metal polluted soils. We assessed the strength of the relationship between earthworm energy reserves and metal availability under conditions of cocktail of metals at low doses and large range of soil parameters. Aporrectodea caliginosa was exposed in laboratory to a panel of soils differing in Cd, Pb and Zn total and available (CaCl2 and EDTA-extractable) concentrations, and in soil texture, pH, CEC and organic-C. Glycogen, protein and lipid contents were recorded in exposed worms. Glycogen contents were not linked to the explaining variables considered. Variable selection identified CaCl2 extractable metals concentrations and soil texture as the main factors affecting protein and lipid contents. The results showed opposite effects of Pb and Zn, high inter-individual variability of biomarkers and weak relationships with easily extractable metals. Our results support the lack of genericity of energy reserves in earthworms exposed to field-contaminated soils.
Показать больше [+] Меньше [-]Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA Полный текст
2014
Hladik, Michelle L. | Kolpin, Dana W. | Kuivila, Kathryn M.
Neonicotinoid insecticides are of environmental concern, but little is known about their occurrence in surface water. An area of intense corn and soybean production in the Midwestern United States was chosen to study this issue because of the high agricultural use of neonicotinoids via both seed treatments and other forms of application. Water samples were collected from nine stream sites during the 2013 growing season. The results for the 79 water samples documented similar patterns among sites for both frequency of detection and concentration (maximum:median) with clothianidin (75%, 257 ng/L:8.2 ng/L) > thiamethoxam (47%, 185 ng/L:<2 ng/L) > imidacloprid (23%, 42.7 ng/L: <2 ng/L). Neonicotinoids were detected at all nine sites sampled even though the basin areas spanned four orders of magnitude. Temporal patterns in concentrations reveal pulses of neonicotinoids associated with rainfall events during crop planting, suggesting seed treatments as their likely source.
Показать больше [+] Меньше [-]The present and future of microplastic pollution in the marine environment Полный текст
2014
Ivar do Sul, Juliana A. | Costa, Monica F.
Recently, research examining the occurrence of microplastics in the marine environment has substantially increased. Field and laboratory work regularly provide new evidence on the fate of microplastic debris. This debris has been observed within every marine habitat. In this study, at least 101 peer-reviewed papers investigating microplastic pollution were critically analysed (Supplementary material). Microplastics are commonly studied in relation to (1) plankton samples, (2) sandy and muddy sediments, (3) vertebrate and invertebrate ingestion, and (4) chemical pollutant interactions. All of the marine organism groups are at an eminent risk of interacting with microplastics according to the available literature. Dozens of works on other relevant issues (i.e., polymer decay at sea, new sampling and laboratory methods, emerging sources, externalities) were also analysed and discussed. This paper provides the first in-depth exploration of the effects of microplastics on the marine environment and biota. The number of scientific publications will increase in response to present and projected plastic uses and discard patterns. Therefore, new themes and important approaches for future work are proposed.
Показать больше [+] Меньше [-]Occurrence and profiles of bisphenol analogues in municipal sewage sludge in China Полный текст
2014
Song, Shanjun | Song, Maoyong | Zeng, Luzhe | Wang, Thanh | Liu, Runzeng | Ruan, Ting | Jiang, Guibin
Extensive use of bisphenol A and its analogues has caused increasing concern over the potential adverse health impacts of these chemicals. In this study, the presence and profiles of 13 bisphenols (BPs) were investigated in 52 municipal sewage sludge samples collected from 30 cities in China. Tetrabromobisphenol A was the most frequently observed analogue (geometric mean: 20.5 ng/g dw). Bisphenol A (4.69 ng/g dw), bisphenol S (3.02 ng/g dw), and bisphenol F (3.84 ng/g dw) were found with similar frequency. Other BP analogues such as tetrachlorobisphenol A, bisphenol AF, bisphenol E, and dihydroxybiphenyl were identified for the first time in sewage sludge in China. Significant correlations were found among BP concentrations, but no relationships were found with wastewater treatment plant characteristics. Profiles of the relative estradiol equivalents suggested that the estrogenic potential of BP mixtures may be associated with the occurrence and contributions of specific analogues.
Показать больше [+] Меньше [-]Improvement of aerosol optical properties modeling over Eastern Asia with MODIS AOD assimilation in a global non-hydrostatic icosahedral aerosol transport model Полный текст
2014
Dai, Tie | Schutgens, Nick A.J. | Gotō, Daisuke | Shi, Guangyu | Nakajima, Teruyuki
A new global aerosol assimilation system adopting a more complex icosahedral grid configuration is developed. Sensitivity tests for the assimilation system are performed utilizing satellite retrieved aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS), and the results over Eastern Asia are analyzed. The assimilated results are validated through independent Aerosol Robotic Network (AERONET) observations. Our results reveal that the ensemble and local patch sizes have little effect on the assimilation performance, whereas the ensemble perturbation method has the largest effect. Assimilation leads to significantly positive effect on the simulated AOD field, improving agreement with all of the 12 AERONET sites over the Eastern Asia based on both the correlation coefficient and the root mean square difference (assimilation efficiency). Meanwhile, better agreement of the Ångström Exponent (AE) field is achieved for 8 of the 12 sites due to the assimilation of AOD only.
Показать больше [+] Меньше [-]Titanium dioxide nanoparticles as carrier facilitate bioaccumulation of phenanthrene in marine bivalve, ark shell (Scapharca subcrenata) Полный текст
2014
Tian, Shengyan | Zhang, Yaodan | Song, Chunzheng | Zhu, Xiaoshan | Xing, Baoshan
To evaluate the impact of titanium dioxide nanoparticles (nTiO2) on the uptake of hydrophobic organic chemicals by marine bivalves, we conducted a comparative bioaccumulation study by exposing clam, Scapharca subcrenata, to phenanthrene (Phe) in the presence and absence of nTiO2. The large surface area of nTiO2 resulted in adsorption of co-existing Phe in aqueous solution to form nTiO2-Phe complexes. Accumulation of nTiO2 was not observed in clams at exposed concentration (500 μg/L) in this study. However, enhanced uptake of Phe by clams was observed in the presence of nTiO2, with ku and BAFs values being 2 and 1.7 times higher than that of Phe alone, respectively. The enhanced uptake can be explained by ingestion of nTiO2-Phe complexes into the gut and subsequent desorption of Phe there. Therefore, nTiO2 as a carrier facilitated the uptake of Phe by marine bivalves.
Показать больше [+] Меньше [-]Improvements in pollutant monitoring: Optimizing silicone for co-deployment with polyethylene passive sampling devices Полный текст
2014
O'Connell, Steven G. | McCartney, Melissa A. | Paulik, L Blair | Allan, Sarah E. | Tidwell, Lane G. | Wilson, Glenn | Anderson, Kim A.
Sequestering semi-polar compounds can be difficult with low-density polyethylene (LDPE), but those pollutants may be more efficiently absorbed using silicone. In this work, optimized methods for cleaning, infusing reference standards, and polymer extraction are reported along with field comparisons of several silicone materials for polycyclic aromatic hydrocarbons (PAHs) and pesticides. In a final field demonstration, the most optimal silicone material is coupled with LDPE in a large-scale study to examine PAHs in addition to oxygenated-PAHs (OPAHs) at a Superfund site. OPAHs exemplify a sensitive range of chemical properties to compare polymers (log Kow 0.2–5.3), and transformation products of commonly studied parent PAHs. On average, while polymer concentrations differed nearly 7-fold, water-calculated values were more similar (about 3.5-fold or less) for both PAHs (17) and OPAHs (7). Individual water concentrations of OPAHs differed dramatically between silicone and LDPE, highlighting the advantages of choosing appropriate polymers and optimized methods for pollutant monitoring.
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